Not applicable.
Not applicable.
The present invention relates to a fluid delivery device, particularly for delivery of combustion air to a heating burner of a motor vehicle and/or for the delivery of heating medium, preferably heating air, through a heating medium duct system of a motor vehicle.
In modern motor vehicles, heating units are increasingly used in order to heat air, for example, when the drive assembly is not running or in addition to the drive assembly, and to supply this heated air to the passenger space or to the driver""s cabin. Such heating devices or supplementary heaters in general have a heating burner in which a fuel, which in general corresponds to the fuel to be burned in the motor vehicle drive assembly, is burned together with supplied combustion air. The resulting heat is transferred to a medium, for example, air or water, circulating in a heat exchange region of the heating burner. The combustion air and also that air or that medium to which the heat is transferred is in general delivered by blowers, pumps, or fans to the heating burner or into the heat exchange region.
In such systems it is of importance to sense the present operating state of the system region to be supplied with the medium to be delivered. For example, in the region of the heating burner it is of importance to sense whether or not combustion is taking place there. In known systems this takes place by temperature sensing of the components thermally affected during the combustion, or for example by optical sensing of a combustion chamber. Whereas the temperature sensing of thermally affected components is a comparatively sluggish measurement method, optical temperature sensing entails problems to the effect that, for example, an optical fiber has to be sealingly conducted into a combustion chamber and that the sensing is furthermore influenced by possible deposits of dirt particles in the region of the sensor.
It is also advantageous to sense whether there is present a possible damming up, for example, intentional or unintentional blockage, of the duct system.
The present invention therefore has as its object to provide a fluid delivery device for delivering a fluid to a system to be supplied with the fluid or respectively, a process for characterizing the operating state of such a system, by means of which the present operating state of this system or the change of the operating state can be concluded in a simple and reliable manner.
According to a first aspect of the present invention, this object is attained by a fluid delivery device, in particular for the delivery of combustion air to a heating burner of a motor vehicle or for the delivery of heating medium, preferably heating air, through a heating medium duct system of a motor vehicle, comprising a delivery member which can be driven to rotate by a drive, a rotary state monitoring arrangement for monitoring the rotary state of the delivery member, and also an operating state sensing arrangement for sensing the operating state of a system to be supplied with fluid by the fluid delivery device, based on the monitoring result of the rotary state monitoring arrangement.
The present invention is based on the knowledge that changes in the operating state of a system supplied with a fluid in general have effects on the flow state of the fluid flowing through this system. Thus for example the fact whether or not combustion is taking place in a heating burner has as a consequence that when combustion is taking place, a markedly higher pressure drop will be present, due to the thermally conditioned expansion of gases present in the combustion chamber, between this system region and that region into which the exhaust gases then emerge, than in a state in which no combustion is taking place. A higher pressure drop however means that the delivery device or the respective delivery member itself has to work against a higher pressure. This however influences the rotary state of this delivery member or requires changes in the operating characteristic of the drive for the delivery member for the maintenance of a given predetermined rotary state. According to the invention, the rotary state of the delivery member is now monitored so that, based on this monitoring result, possibly a changed operating state of the drive of the delivery member, for example, the change of a drive signal, can have as a consequence that statements can be made about the operating state of the system supplied with the delivered fluid. For example, if the rpm of the delivery member falls when the operating state is unchanged, i.e., for example with unchanged control of the drive, this is thus an indication that an increase of the flow resistance has occurred in the downstream duct system. In the case of a heating burner, it can thus be concluded that this has ignited.
For example, it can be provided that the drive in the device according to the invention is an electric motor drive, that a control element is allocated to the electric motor drive and emits to the electric motor drive a control signal characterized by at least one control value and based on the monitoring result, and that the operating state determining arrangement determines the operating state of the system based on the control values and/or a time change of the same. In this aspect of the present invention, a value which occurs anyway in normal operation is thus evaluated for the characterization or sensing of the operating state of the system to be supplied with fluid. Thus no additional constructional measures are required on such a system such as the provision of sensors or the like.
For example, it can be provided that the operating state determining arrangement senses the presence of a given operating state when the control value, and/or the time course of it, reaches a predetermined threshold value. The control value can be, for example, a mark/space ratio of an electrical quantity, which can for example be the applied voltage, supplied to the electric motor drive.
In an alternative embodiment as already mentioned hereinabove, it can be provided, for example, that the operating state determining arrangement senses the operating state based on the rpm of the delivery member or a value related thereto, or the time change of the same.
The present invention is furthermore concerned with a heating system, particularly for a motor vehicle, in which a fluid delivery device according to the invention is provided for the delivery of combustion gas, preferably combustion air, to the combustion chamber of a heating burner, and/or a fluid delivery device according to the invention is provided for the delivery of a heating medium, preferably heating air, by means of a heating medium duct system.
According to a further aspect of the present invention, the object stated hereinabove is attained by a process for the characterization of the operating state of a system to be supplied with a fluid, preferably gas, wherein the fluid delivery device includes a delivery member which can be driven to rotate, comprising the following steps: producing a rpm value reproducing the rpm of the delivery member, monitoring the rpm value, recovery of information characterizing the operating state of the system, based on the rpm value and/or a related control value for a drive of the delivery member.
As already stated hereinabove, the operating state of the system supplied with fluid, or a change of the operating state, can thus be concluded from monitoring the value reproducing the rpm of the delivery member according to the principles of the present invention.
For example, it can be provided that the control value reproduces a mark/space ratio of an electrical quantity supplied to an electric motor drive of the delivery member. This quantity can be, for example, the voltage applied to the electric motor drive.
When using electric motor drives in combustion air delivery systems of heating burners, e.g., supplementary heaters in motor vehicles, the procedure is in general that the rpm of the delivery member is kept to a substantially constant value by means of a corresponding control loop. This value is set such that while combustion is taking place and the flow resistance for the supplied gas resulting in a known manner is set to the desired or required volume flow (=fluid volume passing through per unit time through a given channel section). In such a system it can then be provided, according to an advantageous aspect of the present invention, that for obtaining a predetermined rpm of the delivery member, the mark/space ratio is set to a variable mark/space ratio value, and that the presence or occurrence of a given operating state of the system is sensed when the mark/space ratio, and/or a time rate of change of the same, reaches a predetermined threshold.
The procedure according to the invention can particularly find application when the system comprises a flow duct system, preferably a heating air duct system, and when the operation of the flow duct system is characterized as to whether and/or to what extent a flow medium passage through the flow duct is prevented. Furthermore, particularly preferably, the use of such a procedure is possible when the system comprises an heating burner, preferably in a motor vehicle, when the fluid comprises gas, preferably combustion air, and when the operating state of the heating burner is characterized as to whether and/or to what extent a combustion is taking place.